1837 - born into an aristocratic family; 1855 - graduated from Aleksandrovsky Lyceum with the silver medal; 1856 - started work in the Ministry of Finances where he spent almost 48 years; 1858 - published his first article "Dopolnenie k ukazateliu, sostavlennomu G.N. Gennadi "Chto pisano o Pushkine" (Addition to the guide created by G.N. Gennadi "What is written about Pushkin"); from 1858 - wrote works on Russian genealogy about the ancestry of Sheremet'evy, Orlovy, Volkonskie, Trubetskie, boyars Nagie, Basmanovy; essays about art, history, geography, numismatics, paleography, bibliography, and literature; 1865 - was appointed the head of the chancellery at the Ministry of Finances, then became a member of the council at the Ministry of Finances, the chairman of "podatnaia" committee, and the director of the tax department; 1870s/1880s - took active part in literature fund as its treasurer, secretary, and committee member; 1882 - published his work "Tsesarevich Pavel Petrovich" (Cesarevich Pavel Petrovich), which was translated into French and German and received the Uvarov's Award;; from 1890 - was a member-correspondent of the Academy of Sciences in the department of history and political science; 1901 - was appointed a member of the State Council on Witte's recommendation; 1902 - was appointed the director of the Imperial public library; the beginning of 1905 - was appointed the chairman in the committee on the press reform, in which he defended the freedom of press and supported the abolition of preliminary censorship for periodicals; until November 24, 1905 - worked on the new "temporary press rules;" 1908 - was released from his position at the State Council; 1911 - published his work "Imperatorskii tsarskosel'skii litsei. Nastavniki i pitomtsy 1811-1843" (The Imprerial Tsarskosel'skii Lyceum. Teachers and Students 1811-1843); 1913 - published a complete collection of works in "Sbornik statei v chest' D.F. Kobeko" (The Collection of Articles in Honor of D.F. Kobeko); 1914 - published his autobiography in the edition "Imperatorskaia publichnaia biblioteka za sto let 1814-1914" (The Imperial Public Library in One Hundred Years 1814-1914); 1918 - was released from the post of the Director of the Public Library; 1918 - died and was burried at Novodevichy cemetery in Petersburg.